A support of this kind and an adjusting unit are disclosed, for example, in European patent publication 0,433,426. This support carries an apparatus in the form of a surgical microscope and the adjusting unit is mounted between a holding arm of the support and the surgical microscope. The surgical microscope can be shifted relative to the holding arm with the adjusting unit. In this way, the center of gravity of the surgical microscope can be shifted relative to the support in order to balance the entire system.
A further support is disclosed in German patent publication 3,147,836. In this publication, the gearing system of the adjusting unit is shown in detail. Here, an adjusting unit includes a cross-slide guide with self-arrestment. It can be seen that the adjusting device is configured so as to be constructively complex.